In step with the development of automobile technologies came the installment of systems for providing convenient driving and riding experiences. Such systems include an electric power steering (hereinafter referred to as EPS) for giving the driver a steering assist, an electronic stability program (or ESP) for preventing lane deviation of a vehicle by comparison/evaluation of the driver's steering intention and controlling the vehicle dynamics, and an electronically controlled suspension (or ECS) for varying the vehicle height depending on the road condition and driving needs to enhance the dynamic stability riding comfort.
FIG. 1 is a block diagram schematically showing a vehicle system equipped with an EPS, an ESP and an ECS. A torque sensor 102 senses the torque caused by the driver's operations of the steering wheel and delivers the same to an electronic control unit (or ECU) of the EPS (hereinafter called EPS ECU at 106), which delivers an assisting current corresponding to the received torque to a motor to provide the steering assist.
A steering angle sensor 104 detects the angle of the driver's operated steering wheel and deliver via a CAN (control area network) to the ECU of the ESP (hereinafter called ESP ECU at 108) and to an ECS ECU 110 where the received steering angle is used to perform the respective stability and suspension controls.
FIG. 2 illustrates the construction of a conventional steering angle sensor. As illustrated, the sensor has a main gear 202 to which a first auxiliary gear 204 and a second auxiliary gear 206 are meshed which have adjacently mounted magneto resistance sensors 208 and 210, respectively. Thus, when the steering wheel is turned, main gear 202 and auxiliary gears 204, 206 are rotated in accord. The rotations of auxiliary gears 204, 206 cause magneto resistance sensors 208 and 210 to interact with magnetic members provided inside of auxiliary gears 204, 206 to produce electrical signals in sine wave repeatedly.
A calculation/control module 212 calculates the steering angle using electric signals from magneto resistance sensors 208 and 210 and transmits the same to other systems via a CAN (Controller Area Network) transceiver 214. However, since the conventional steering sensor involved the CAN communication in transmitting the calculated steering angles, the dedicated system of CAN transceiver 214 for such CAN communications is necessary which increases the manufacturing cost.
Especially, in the state of the art where conventional torque sensor and steering angle sensor are being developed into integrated modules as torque-steering angle sensors, such an arrangement of the separate CAN communication modules for transmitting the steering angle data to systems encounters the problem of inefficiency.